Install a humidifier machine in a central location, such as the living room or kitchen. If you have a large, two-story home, you may consider installing multiple humidifiers for best results. As humidifiers vary among manufacturers, refer to the installation instructions or have a professional install it for you.
Keep windows closed during the day to retain water vapor. Check that all door frames in your home are weather sealed to prevent humidity loss.
Leave the bathroom door slightly ajar while showering or bathing. The water vapor produced by a shower will help increase the entire home's humidity. Alternatively, you can draw a hot bath or run a hot shower for several minutes with the door open.
Place a large bowl of water in each room of your house. The water will slowly evaporate and help humidify the room. Replace the water every two days.
Boil a pot of water on your stove on a regular basis. This effect is similar to running a hot shower because it releases water vapor directly into the air.